News in Brief

Amgen Halts GDNF Study

As of September 1, the Amgen company has halted all clinical trials of GDNF, a neuronal growth factor for treating advanced Parkinson's. This decision was reviewed and agreed upon by the U.S. Food and Drug Administration (FDA), Health Canada (HC) and the Medicines and Healthcare Products Regulatory Agency (MHRA) in the U.K.

The announcement, which is disappointing to the Parkinson's community, follows a mid-summer report that showed that Phase II trials of GDNF failed to demonstrate any clinical improvement after six months of use.

Amgen cites two reasons for discontinuing trials in the interest of participant safety. The first reason was found in pre-clinical data from non-human primates that had been treated in the highest dosage group for six months, followed by a three-month washout period. Researchers discovered a significant loss of specialized neurons in the cerebellum, which is a part of the brain involved in coordinating movement. This finding had not been seen before in any of the previous studies of GDNF. Investigators do not yet know the cause of this brain-cell loss but they will continue to collect data from the study and will submit their findings to the FDA.

The other major factor in the decision to stop the trial was the detection of "neutralizing antibodies" in two study participants. Antibodies are made by cells to defend the body against foreign material. Neutralizing antibodies could clear the body of the GDNF drug, as well as possibly reduce the body's natural supply of GDNF. It is unclear if such a reduction in natural GDNF is harmful, and researchers are still testing blood samples to determine the cause and risks of this phenomenon. Blood sample collections will continue for at least one year.

In a response to this announcement, Dr. Stanley Fahn, PDF Scientific Director, acknowledged that, "Although this news is disappointing, there remains a great deal of work to be done before we can decide, as a scientific community, what potential this compound may or may not have."

FDA Approves Parcopa™, Dissolving Formula of Carbidopa/Levodopa

On August 30, Schwarz Pharma announced FDA approval of a readily dissolvable formulation of carbidopa/levodopa called Parcopa™. These tablets are available in the same strengths as regular Sinemet® and may be used in the same dosage schedules. This new formulation, which should now be available in pharmacies everywhere, may be helpful to people who experience morning rigidity and off-periods as it does not require water or swallowing a whole pill.

The product utilizes Schwarz Pharma's RapiTab™ technology, enabling the tablets to dissolve on the tongue without fluids. Patients should note that Parcopa™ is not a continuous-release formulation and should not be used in place of Sinemet CR®. Like all dopamine drugs, the most common side-effects of Parcopa™ are dyskinesias and nausea.

Schwarz Pharma is operating a coupon program to keep the price of Parcopa™ similar to that of carbidopa/levodopa. To receive this $20 coupon, visit www.parcopa.com or ask your physician for more information.

For more information on the latest news in Parkinson's, visit www.pdf.org. We regularly update our website with commentary and literature on scientific and community news.